MIAMI (AP) — Patient advocates say some insurance companies are making HIV and AIDS drugs unaffordable in plans issued through the Affordable Care Act by shifting much of the cost to customers.

While the issue applies broadly to all patients with chronic illnesses that require expensive medication, HIV and AIDS advocates say they were the first to file a formal complaint with the government about pricing.

Under President Obama’s health law, insurance companies are forbidden from turning away consumers with pre-existing conditions. But advocacy groups allege insurance companies are discouraging HIV and AIDS patients, who are expensive to cover, by requiring them to pay a percentage of costly medications instead of a flat co-pay, essentially pricing the medications out of reach.

Several insurance companies are also impeding access to services by requiring re-authorization for drugs consumers have been taking for years or making the claims process difficult, says Carl Schmid, deputy executive director of The AIDS Institute. The group filed a complaint with U.S. Health and Human Services officials this summer against four Florida insurance companies, and advocates in other states are considering similar action.

The complaint filed with federal health officials alleges Humana, CoventryOne, Cigna and Preferred Medical are violating the federal health law by discouraging consumers with HIV and AIDS from choosing those plans because they wouldn’t be able to afford the high co-insurance rates.

Georgia advocates are planning to file a similar complaint with federal officials, said Dr. Melanie Thompson, who has several patients unable to afford the medicines under their new insurance plans. Advocacy groups say they are finding similar problems with some exchange plans in Ohio, California and Illinois.

HHS said it’s reviewing the complaint in Florida but declined further comment. Advocates say intervention by the federal government would also benefit patients who take expensive medications for chronic conditions such as blood cancer and rheumatoid arthritis.

The problem arises from how drugs are priced by insurance companies. For the bulk of drugs, consumers pay just a fixed amount, usually about $30 to $45 a prescription. However, insurance companies have taken some of the most expensive drugs and put them in a special category, where they require patients to pay as much as 50 percent of the total cost.

While insurance companies face high costs in treating many cancer and hepatitis patients, the costs are more acute when a patient has a chronic, incurable health issue — for example HIV or multiple sclerosis — since they will have to take the expensive medications for the rest of their lives.

“By putting the drugs that are recommended up on the highest tiers in an unaffordable place they are in essence discriminating against people with HIV because these are the lifesaving drugs they require to survive,” Thompson said. Advocates are quick to point out that many of the seriously ill patients now enrolled in ACA plans had trouble finding insurance before the law was passed, but say something needs to be done about the drug costs.

An HIV patient in north Georgia who asked not to be named bought a silver Kaiser Permanente plan for himself and his partner, paying a roughly $110 monthly premium, with the government paying a $900 subsidy. Doctor visits and blood pressure medicines fell under cheap co-pays, but he was shocked to find the plan required him to pay half the cost of his HIV medicine — about $1,800 a month for his share, he said.

The patient, who had been uninsured for nearly two decades before enrolling through the ACA, asked not to be identified because he works in health care and is worried about the stigma of HIV.

For now he’s getting his medication for free from an advocacy group, but the 49-year-old patient says he doesn’t know what he’ll do when that ends.

Kaiser Permanente Georgia said in a statement that it provides financial grants to organizations like one helping the patient and understands “the burden that high-priced pharmaceuticals can place on patients.”

The Affordable Care Act bans insurers from charging an individual more than $6,350 in out-of pocket costs a year and no more than $12,700 for a family policy. But patient advocates warn those with serious illnesses could pay their entire out-of-pocket cap before their insurance kicks in any money. Money paid toward premiums doesn’t count toward the caps.

In Ohio, Anthem Blue Cross Blue Shield, Coventry, Humana and Medical Mutual put every HIV drug, including generics, on the highest tiers or categorized them as specialty drugs that require consumers to pay 20 to 50 percent co-insurance after satisfying deductibles, according to the Aids Drug Assistance Programs in Ohio. The group says a patient on a common drug regimen of Truvada and Isentress could still pay $1,200 a month on Humana’s plan after meeting a $6,000 deductible.

The AIDS Foundation of Chicago said HIV medications are likely unaffordable in plans offered by Aetna, Coventry, Health Alliance, and Humana. In most cases, medications were placed on the highest tier, requiring co-insurance as high as 50 percent, which could cost a patient more than $1,100 a month for Atripla, a common, three-drug regimen.

The organization complained about the situation in a letter to state insurance officials. The state responded last month with a bulletin notifying insurers that plans can be considered discriminatory if they impose unreasonable prescription restrictions or redundantly require pre-authorization for refills without justification.

In an attempt to prevent similar problems, Maryland lawmakers passed a bill that would limit cost sharing for specialty drugs to $150 for a 30 day supply.

Federal health officials and state regulators are using a tool to spot plans that vary significantly from the majority. But if a large number of insurance companies take the same approach to costly drugs for chronic conditions, it’s harder for the tool to find the outliers, experts say.

“Unfortunately, these types of issues are going to be difficult to spot in the initial plan approval process given the resources state and federal regulators have at their disposal,” said Monica Lindeen, Montana’s state insurance commissioner and president of the National Association of Insurance Commissioners.

Insurance companies said in separate statements that their plans follow the latest HHS guidelines, cover all medically necessary HIV drugs and offer a variety of choices.

Around the country, state and local groups like the Aids Drug Assistance Programs (ADAP) and Ryan White Programs help patients with prescription drug costs, but typically focus on the uninsured and underinsured.

Drew Dalire, 43, was in good health when he bought a plan in December from Humana under the Affordable Care Act, but he was diagnosed weeks later with HIV after a hospitalization. His said he found out his three-drug regime would cost about $1,800 a month after his $500 deductible.

Humana eventually let the Orlando resident, who works in set design, drop the plan and enroll with another insurer that he says offers better coverage. Ryan White Programs is paying for one of his medications.

“People like Coventry and Cigna and Humana are taking advantage of us when they’re supposed to help us,” said Dalire.